Call sysfb_disable() from aperture_remove_conflicting_pci_devices()
before removing PCI devices. Without, simpledrm can still bind to
simple-framebuffer devices after the hardware driver has taken over
the hardware. Both drivers interfere with each other and results are
undefined.
Reported modesetting errors [1] are shown below.
---- snap ----
rcu: INFO: rcu_sched detected expedited stalls on CPUs/tasks: { 13-.... } 7 jiffies s: 165 root: 0x2000/.
rcu: blocking rcu_node structures (internal RCU debug):
Task dump for CPU 13:
task:X state:R running task stack: 0 pid: 4242 ppid: 4228 flags:0x00000008
Call Trace:
<TASK>
? commit_tail+0xd7/0x130
? drm_atomic_helper_commit+0x126/0x150
? drm_atomic_commit+0xa4/0xe0
? drm_plane_get_damage_clips.cold+0x1c/0x1c
? drm_atomic_helper_dirtyfb+0x19e/0x280
? drm_mode_dirtyfb_ioctl+0x10f/0x1e0
? drm_mode_getfb2_ioctl+0x2d0/0x2d0
? drm_ioctl_kernel+0xc4/0x150
? drm_ioctl+0x246/0x3f0
? drm_mode_getfb2_ioctl+0x2d0/0x2d0
? __x64_sys_ioctl+0x91/0xd0
? do_syscall_64+0x60/0xd0
? entry_SYSCALL_64_after_hwframe+0x4b/0xb5
</TASK>
...
rcu: INFO: rcu_sched detected expedited stalls on CPUs/tasks: { 13-.... } 30 jiffies s: 169 root: 0x2000/.
rcu: blocking rcu_node structures (internal RCU debug):
Task dump for CPU 13:
task:X state:R running task stack: 0 pid: 4242 ppid: 4228 flags:0x0000400e
Call Trace:
<TASK>
? memcpy_toio+0x76/0xc0
? memcpy_toio+0x1b/0xc0
? drm_fb_memcpy_toio+0x76/0xb0
? drm_fb_blit_toio+0x75/0x2b0
? simpledrm_simple_display_pipe_update+0x132/0x150
? drm_atomic_helper_commit_planes+0xb6/0x230
? drm_atomic_helper_commit_tail+0x44/0x80
? commit_tail+0xd7/0x130
? drm_atomic_helper_commit+0x126/0x150
? drm_atomic_commit+0xa4/0xe0
? drm_plane_get_damage_clips.cold+0x1c/0x1c
? drm_atomic_helper_dirtyfb+0x19e/0x280
? drm_mode_dirtyfb_ioctl+0x10f/0x1e0
? drm_mode_getfb2_ioctl+0x2d0/0x2d0
? drm_ioctl_kernel+0xc4/0x150
? drm_ioctl+0x246/0x3f0
? drm_mode_getfb2_ioctl+0x2d0/0x2d0
? __x64_sys_ioctl+0x91/0xd0
? do_syscall_64+0x60/0xd0
? entry_SYSCALL_64_after_hwframe+0x4b/0xb5
</TASK>
The problem was added by commit 5e0137612430 ("video/aperture: Disable
and unregister sysfb devices via aperture helpers") to v6.0.3 and does
not exist in the mainline branch.
The mainline commit 5e0137612430 ("video/aperture: Disable and
unregister sysfb devices via aperture helpers") has been backported
from v6.0-rc1 to stable v6.0.3 from a larger patch series [2] that
reworks fbdev framebuffer ownership. The backport misses a change to
aperture_remove_conflicting_pci_devices(). Mainline itself is fine,
because the function does not exist there as a result of the patch
series.
Instead of backporting the whole series, fix the additional function.
v2:
* expand justification for this fix (Greg)
Reported-by: Andreas Thalhammer <andreas.thalhammer-linux@xxxxxxx>
Reported-by: Thorsten Leemhuis <regressions@xxxxxxxxxxxxx>
Signed-off-by: Thomas Zimmermann <tzimmermann@xxxxxxx>
Tested-by: Andreas Thalhammer <andreas.thalhammer-linux@xxxxxxx>
Fixes: cfecfc98a78d ("video/aperture: Disable and unregister sysfb devices via aperture helpers")
Cc: Thomas Zimmermann <tzimmermann@xxxxxxx>
Cc: Javier Martinez Canillas <javierm@xxxxxxxxxx>
Cc: Zack Rusin <zackr@xxxxxxxxxx>
Cc: Daniel Vetter <daniel.vetter@xxxxxxxx>
Cc: Daniel Vetter <daniel@xxxxxxxx>
Cc: Sam Ravnborg <sam@xxxxxxxxxxxx>
Cc: Helge Deller <deller@xxxxxx>
Cc: Alex Deucher <alexander.deucher@xxxxxxx>
Cc: Zhen Lei <thunder.leizhen@xxxxxxxxxx>
Cc: Changcheng Deng <deng.changcheng@xxxxxxxxxx>
Cc: Maarten Lankhorst <maarten.lankhorst@xxxxxxxxxxxxxxx>
Cc: Maxime Ripard <mripard@xxxxxxxxxx>
Cc: dri-devel@xxxxxxxxxxxxxxxxxxxxx
Cc: Sasha Levin <sashal@xxxxxxxxxx>
Cc: linux-fbdev@xxxxxxxxxxxxxxx
Cc: <stable@xxxxxxxxxxxxxxx> # v6.0.3+
Link: https://lore.kernel.org/dri-devel/d6afe54b-f8d7-beb2-3609-186e566cbfac@xxxxxxx/T/#t # [1]
Link: https://patchwork.freedesktop.org/series/106040/ # [2]
---
drivers/video/aperture.c | 11 +++++++++++
1 file changed, 11 insertions(+)
diff --git a/drivers/video/aperture.c b/drivers/video/aperture.c
index d245826a9324..cc6427a091bc 100644
--- a/drivers/video/aperture.c
+++ b/drivers/video/aperture.c
@@ -338,6 +338,17 @@ int aperture_remove_conflicting_pci_devices(struct pci_dev *pdev, const char *na
resource_size_t base, size;
int bar, ret;
+ /*
+ * If a driver asked to unregister a platform device registered by
+ * sysfb, then can be assumed that this is a driver for a display
+ * that is set up by the system firmware and has a generic driver.
+ *
+ * Drivers for devices that don't have a generic driver will never
+ * ask for this, so let's assume that a real driver for the display
+ * was already probed and prevent sysfb to register devices later.
+ */
+ sysfb_disable();
+
/*
* WARNING: Apparently we must kick fbdev drivers before vgacon,
* otherwise the vga fbdev driver falls over.
--
2.38.0
